Figure 1

Insulin like growth factor binding protein 7 (IGFBP7) is downregulated in multiple myeloma. (A) IGFBP7 expression levels were analysed by gene expression profiling of memory B cells (MBC), polyclonal plasmablastic cells (PPC) as well as of CD138+ purified cells from healthy donors (BMPC), newly diagnosed myeloma patients (MM), patients suffering from monoclonal gammopathy of undetermined significance (MGUS) and human MM cell lines (HMCLs). Grey data points indicate an absent, black data points a present Affymetrix detection call. The asterisk indicates statistical significance (* P < 0.02). IGFBP7 expression analysis by qPCR (B) and flow cytometry (C) confirmed heterogeneous expression levels in myeloma cell lines. (B) Expression levels by qPCR are displayed relative to peripheral blood mononuclear cells (PBMCs) of healthy donors (n = 3). IGFBP7 expression in PBMCs was arbitrarily set at 1. (C) Intracellular staining of MM cells for IGFBP7 protein levels confirmed the variable expression of IGFBP7 transcripts observed by qPCR. MM cells were stained with either anti-IGFBP7 antibody (black lines) or control antibody (light grey lines), followed by PE-conjugated anti-goat antibody.